1. Field of the Invention
The present invention relates to a hybrid integrated circuit (hybrid IC) component into which a thin film integrated circuit and a passive circuit including a resistor, an inductor, a capacitor or the like are assembled. The hybrid integrated circuit is also called a composite integrated circuit. More particularly, the invention relates to a composite integrated circuit into which a thin film integrated circuit formed on a substrate and at least one of an inductor having a lamination structure of a foundation material containing an electrically insulating magnetic material and a conductor, and a capacitor having a lamination structure of a foundation material containing a dielectric material and a conductor are integrated with each other.
2. Prior Art
Up to the present, there has been known a capacitor or inductor formed by a laminating method, or a hybrid component thereof. Generally, in the hybrid component, powders of a magnetic material and a dielectric material are temporarily fired at a relatively low temperature, and then mixed with a binder thereby producing a paste. The paste is printed on a temporary support substrate in the form of a sheet in such a manner that the paste is capable of being readily separated from the substrate. Further, a coil conductor or an electrode conductor is laminated on the paste-printed substrate, and these materials are alternately laminated.
The laminated body is fired at a high temperature (for example, 800.degree. to 900.degree. C. or 870.degree. to 900.degree. C. in the case of Ni-Cu-Zn based ferrite; and 1400.degree. to 1500.degree. C. in the case of TiO.sub.2 based or BaTiO.sub.3 based ceramics), to thereby obtain a laminated applied component.
Furthermore, there has been known a composite component in which the lamination applied component of a capacitor or an inductor is used for a substrate, and a bare chip IC is provided on the ceramic substrate including the L and C circuit elements.
The schematic explanatory diagram of the composite component is shown in FIG. 2. In FIG. 2, a substrate includes two circuits of L and C. By a conventional method, a magnetic material or a dielectric material and an electrode material are alternately laminated on a temporary support substrate, to thereby form a laminated body. After the laminated body is dried, the temporary support substrate is separated from those materials. Thereafter, the laminated body is fired at a high temperature, to thereby form a substrate 200 including the circuit elements of L and C shown in FIG. 2. In the figure, an inductor portion 202 is formed on a capacitor portion 201, however, this arrangement is altered as occasion demands.
On the substrate including the L and C circuits thus organized, a bare IC chip 204 is disposed. An output terminal 205 of the IC chip 204 and an electrode 206 provided on the substrate are connected to each other through wire bonding 207 or the like. The IC chip 204 is covered with a package 208 made of plastic or ceramics, resulting in the composite component shown in FIG. 2.
In the hybrid integrated circuit component thus organized, when forming the laminated body component, the laminated body is formed on the temporary support substrate by a screen printing or the like. Then, after the laminated body is dried, the temporary support substrate must be separated from the laminated body.
Further, in addition to a connecting step of electrically connecting the substrate of the laminated chip to the IC chip and the like, complicated steps such as a step of packaging the whole device and the like are required.
Still further, because the laminated components such as a capacitor, an inductor, etc. and the IC chip are manufactured based on the different specifications respectively, the combination of these components has its shape lowered in matching property, and the thickness of the combination is increased, resulting in impossibility of sufficiently mounting the components to high density.
As is apparent from FIG. 2, in the conventional hybrid integrated circuit, a single thin film integrated circuit chip is directly mounted on a single laminated body, and the thin film integrated circuit chip and the single laminated body are properly connected to each other on the substrate in accordance with a circuit design to thereby constitute a desired component. Since the passive element component of the laminated type such as a capacitor, an inductor or the like is of a thick film laminated body, it can be more sufficiently designed in characteristics for the respective functions. However, the thin film integrated circuit chip cannot provide more than a single function to the circuit formed on the semiconductor substrate. For that reason, a single hybrid integrated circuit component was formed as a component having a single function.
A conventional hybrid integrated circuit component shown in FIG. 7 is constituted in such a manner that a bare thin film integrated circuit chip 701 is mounted on a laminated body 706 mainly consisting of a laminated capacitor 703, a laminated inductor 704, and a resistor 705, and both are electrically connected to each other through wire bonding with a metallic wire 707, and the whole components are molded with a resin 708.
The thin film integrated circuit chip 701 used in FIG. 7 is constituted in such a manner that an integrated circuit such as a thin film transistor and the like is formed through the semiconductor process with an active silicon layer which is formed on a substrate such as, quartz or the like.
There has been already proposed a hybrid integrated circuit component in which the laminated body of a passive element such as a laminated type conductor or the like and a substrate having a thin film transistor and the like adhere to each other with a metallic bump so as to be electrically connected to each other (for example, Japanese Patent Unexamined Publication No. Hei 4-260363).
However, the conventional hybrid integrated circuit component has such a problem that, because the thin film integrated circuit chip is expensive although the integrated body constituting the passive element portion is formed at a very low price, the entire hybrid integrated circuit component is very expensive.
Furthermore, since the electrically connection of the laminated body and the bare thin film integrated circuit chip is performed through wire bonding, the metallic wire is liable to twist and separate, whereby the productivity is lowered and reliability is lacked.
Still further, even though the laminated body and the integrated circuit substrate are connected to each other with the metallic bump or the like, the substrate constituting the integrated circuit is made of glass or the like, as the result of which the sufficient element characteristics can not be always obtained.
There is a case where a ceramic substrate available inexpensively is used as the substrate constituting the thin film integrated circuit for the composite integrated circuit component with the above-mentioned structure. However, since the ceramic substrate has a rough surface, if a semiconductor layer for formation of the thin film integrated circuit elements is directly formed on the substrate, the rough surface of the ceramic substrate adversely affects the surface of the semiconductor layer, resulting in such a problem that, for example, the channel length of the semiconductor element is changed with the loss of the circuit element characteristics.
Further, there has been proposed an experiment to not form the thin film integrated circuit chip and the laminated body consisting of the passive element by different processes, and to built a large-capacitance capacitor within a Si substrate of an LSI by the thin film forming process to form the integrated circuit component (Nikkei Electronics, May 24, 1993, pp. 82 to 87). In this case, the capacitance of the capacity assembled in the Si substrate is limited to thereby insufficiently perform the function. Also, in the conventional composite integrated circuit component, the laminated body forming its passive element portion is formed by the thick film forming process through firing. Therefore, even in the case of laminating the dielectric material layer or the magnetic material layer into a multi-layer structure, the laminated body per se is very high in productivity and low in manufacturing costs. If the number of the inductors or the capacitors is reduced, the composite integrated circuit component is made small in size.
In the case of mounting a thin film integrated circuit on a laminated body, the laminated body has to have a sufficient area to hold the IC on it. As a result, there arises such a problem that the size of the laminated body can not be sufficiently reduced.
In the case an LSI having a large capacitance built therein, the capacitance should be formed adjacent to an integrated circuit on one substrate. As a result, the size of the device is unavoidably increased.